This invention relates to microwave ovens and especially to a compact and simple feed system which achieves more uniform cooking of a variety of food loads.
Motional microwave power feeds have been shown to give better cooking performance than stationary linear polarized feeds. However, motional feeds employing rotary joints to directly excite a moving radiator may have problems of reliability. On the other hand, a simple "parasitic" indirectly excited moving radiator, commonly known as a mode stirrer, is more reliable but is not as effective as a directly excited motional feed in producing uniform heating. The reason for its inferior performance is that the common mode stirrer does not rotate the polarization completely around.
The configurations described here represent a new approach which allow the complete rotation of the polarization without the need for a rotary joint. In this way the heating uniformity is improved in a simple way without significant sacrifice in reliability.